Complications
A Adverse cognitive impairment
2. Postoperative cognitive dysfunction
a) Postoperative cognitive dysfunction (POCD) is characterized by persistent and long-term deterioration of cognitive performance after anesthesia and surgery.
b) POCD is often associated with cardiac and orthopedic surgery, but it can also accompany other surgical procedures. Cognitive dysfunction in both cardiac and noncardiac surgery has largely focused on older adults, who might have a greater vulnerability to neurologic deterioration as a consequence of the aging process.
c) POCD is difficult to diagnose because it requires sophisticated neurophysiologic testing, including preoperative baseline tests.
d) Patient risk factors include age, lower levels of education, and history of stroke even without residual deficit.
e) Increased 1 year mortality is associated with patients who demonstrate cognitive decline at both hospital discharge and 3 months postop.
a) The term confusion is used to describe the general affect and behaviors of patients; however, it is not specific and appears to have a great deal in common with delirium.
b) Confusion (a form of transient cognitive dysfunction) after anesthesia relates to disorders of orientation and is usually a relatively short-lived transient cognitive dysfunction.
c) Confusion after anesthesia is a normal occurrence, and it is suggested that patients refrain from engaging in activities requiring rapid responses for at least 48 hours postanesthesia.
a) Delirium (or acute mental confusion) is transient, often abrupt and fluctuating, typically reversible, and related to increased risk of postoperative adverse reactions (i.e., pulmonary edema, myocardial infarction, respiratory failure, pneumonia, and death), increased length of hospital stay, increased health care cost, and poor functional and cognitive recovery. The onset occurs in hours to days after anesthesia and surgery.
b) Key symptoms include anxiety, incoherent or disorganized thinking and perceiving, reduced ability to sustain and shift attention to new external stimuli, and agitated behavior. There is sensory misperception; a disordered stream of thought; and difficulty in shifting, focusing, and sustaining attention to both external and internal stimuli. Irrelevant stimuli can easily distract the delirious individual.
c) The cause of postoperative delirium is multifactorial. Virtually any drug with central nervous system effects has been implicated, including narcotics (especially meperidine), benzodiazepines, and drugs that possess anticholinergic properties (except glycopyrrolate). Common are perceptual disturbances that result in misinterpretations, illusions, and hallucinations. Disturbances of sleep–wakefulness and psychomotor activity are present.
d) Precipitants are related to physical illness (e.g. cardiovascular disease), infection, hormone disorders, or nutritional deficiencies. Most frequent precipitants are metabolic disturbances; fluid and electrolyte imbalances; drug and alcohol toxicity; and unfamiliar and excessive sensory-environmental stimuli.
e) Delirium may be life threatening and is a medical emergency. Delirium occurs in about 20% of elderly surgical patients and is more common in patients undergoing orthopedic procedures (i.e., femoral fractures) with an incidence rate of 28% to 60% in this surgical population. Thirty-two percent of patients who had coronary artery bypass surgery reported postoperative delirium.
f) Early identification and prompt treatment of the causes of delirium prevent irreversible dementia and death, with interventions targeted at reversing physiologic disturbances and preventing sensory deprivation.
g) The choice of general anesthesia or regional anesthesia does not appear to be a factor, especially when sedation is used in conjunction with regional anesthesia (RA).
h) Management focuses on reversible risk factors such as current meds, pain management, and a better sleep environment. Haloperidol in doses no greater than 1.5 mg can be helpful, especially for agitated delirium. When administered prophylactically, it may reduce the severity of duration but not the incidence of delirium.
a) Awareness, the unambiguous recall of events during general anesthesia, has an incidence of 0.18% in the United States. The term recall, the ensuing retention of an event after it occurs, is a better description of the phenomena; however, episodes of awareness are strong predictors of dissatisfaction with anesthesia care.
b) For every 1000 adult patients who receive a general anesthetic, as many as one or two will express the occurrence of awareness or recall; this figure is higher in children. Inadequate depths of anesthesia may lead to awareness and recall; accounts of awareness rely on patient recollection.
c) Although patient recollection of awareness or recall may be reported, most do not complain of recalling pain during the procedure. Instead, patients report “dreamlike” experiences and auditory remembrance during which they are not in distress.
d) Reports of intraoperative awareness should be addressed immediately and thoroughly evaluated to obtain information for quality assurance.
e) Management of awareness begins when patients are given an opportunity to discuss the causes of the event with the anesthesia provider to gain a clearer understanding of the circumstances surrounding the experience and follow-up consultation.
f) The awareness experience is certainly a distressing event and outside normal operative occurrences. These stressful events may lead to nightmares and sleep disturbances, intrusive memories and avoidance behavior, emotional numbing and forgetting, and other diagnostic criteria for posttraumatic stress disorder.
g) The causes of intraoperative awareness are diverse and are listed in the following box.
h) Awake paralysis, one of the most feared causes, is possibly the most preventable. Awake paralysis is related to lapses in practitioner vigilance and can lead to out-of-sequence neuromuscular blockade administration and medication error.
i) Prevention of awareness is the best treatment for awareness. The American Association of Nurse Anesthetists has an awareness policy that helps identify at-risk patients and measures to address and possibly avoid perioperative awareness. This anesthesia care plan to reduce the incidence and severity of awareness includes the fundamental practices listed in the box on pg. 600.
